Focusing an outside view (light) down a tube then expanding it

In summary, the conversation discusses the concept of focusing outside light through a tube and magnifying it to display an outside view. The lenses used for this process are ordinary convex lenses and the distance from the lens to the wall must be equal to the focal length for a clear image. However, the image may not be very large and an alternative method of creating a camera obscura using a pinhole is suggested.
  • #1
tim999
1
0
Can someone please tell me if there is name for focusing the outside light to a point down a tube then magnifying it back showing the outside view?

E.g. having the lenses focus on a hill side then focus down a 1 meter tube then enlarge onto wall.

If there is no name for this what type of lenses do I need to make it?

thanks
 
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  • #2
welcome to pf!

hi tim999! welcome to pf! :wink:

that's just an ordinary convex lens

the distance from the lens to the wall must be equal to the focal length of the lens, or the image will be blurred

but the image won't be very large, it'll be the focal length times tanθ, where θ is the angle subtended (at your eye) by the hillside

(and the larger the image, the fainter it will be)

you might be better off turning your room into a camera obscura, using a pinhole instead of a lens …

see http://en.wikipedia.org/wiki/Camera_obscura :smile:​
 

1. How does focusing an outside view (light) down a tube work?

Focusing an outside view (light) down a tube involves using lenses to manipulate the path of light. The first lens, known as the objective lens, collects and focuses the light onto a second lens, called the eyepiece, which then magnifies the image for our eyes to see.

2. What is the purpose of expanding the view after focusing it down a tube?

Expanding the view after focusing it down a tube allows for a larger and clearer image to be seen. This is particularly useful in microscopy, astronomy, and other fields where magnification and clarity are important.

3. How does the shape and size of the tube affect the focused image?

The shape and size of the tube can affect the focused image in several ways. A wider tube can allow for more light to enter, resulting in a brighter image. A longer tube can increase the magnification, while a shorter tube can decrease it. Additionally, the material and quality of the tube can also impact the image.

4. Is there a limit to how much the view can be expanded after focusing it down a tube?

Yes, there is a limit to how much the view can be expanded after focusing it down a tube. This limit is based on the optical properties of the lenses and the length of the tube. The maximum magnification that can be achieved is called the maximum useful magnification.

5. What are some common uses for focusing an outside view (light) down a tube and expanding it?

Focusing an outside view (light) down a tube and expanding it is used in a variety of fields, such as microscopy, astronomy, and photography. It allows for magnification and clarity in observing small or distant objects. It is also used in various medical and scientific instruments, such as endoscopes and telescopes.

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